The HTML program Transmission Line Calculator tlc-e.htm makes use of a JavaScript extention file tlc.js and calculates the characteristic impedance as well as the inductance/m and capacitance/m of a round inner conductor in 8 different outer conductor structures. As a 9th structure the two-wire line is provided. The program can be tested here online. It "speaks" English and German.

If you want to download it to your computer, you may load the ZIP-Archive which contains the following files:

• tlc.htm, tlc-info.htm, (German version including info page)
• tlc-e.htm, tlc-info-e.htm (English version including info page)
• tlc.js (JavaScript file, common to both languages), as well as
• 12 diagrams, which are used in the HTML files and
• the 18-page-paper describing the background and theory, both in German and English.

Special interest should find Formula (3) with the structural factor k=1,08 because it will calculate the characteristic impedance of a round inner conductor in a square outer conductor even for thick inner conductors and/or small distances between inner and outer conductor with previously unknown accuracy.
Thus - hopefully - the 'strange' formula presented first in the 1956 Handbook for Radio Engineers and which has been copied since then again and again (see e.g. in "rfcafe") will finally cease to mislead engineers throughout the world.

Last changed: 2. July 2018